Pedal operated demagnetizing control switch



Oct. 28, 1958 A. E. wEsTBuRGH 2,858,383

PEDAL OPERATED DEMAGNETIZING CONTROL SWITCH l Filed July 27, 1955. l 2 Sheets-Sheet 1 OFI/K571i. H 7700/ /MJULA T10/r ms Arofmyf Oct. 28, 1958 A. E. wl-:sTBURGH 2,858,383

PEDAL OPERATED DEMAGNETIZING CONTROL SWITCH Filed July 27, 1955 2 Sheets-Sheet 2 INVENTOR, ARTHUR EWESTBURGH,

United States Patent O PEDAL OPERATED DEMAGNETIZING CONTROL SWITCH Arthur E. Westburgh, Jamestown, N. Y.

Application July 27, 1955, Serial No. 524,662

1 Claim. (Cl. 200-6) This invention relates to a switch operable to control a magnetic circuit as well as the circuit for the main or driving operation from the same source of current without cutting off that source of current.

The invention is capable of various applications but is particularly useful where ball bearing rings or other objects are magnetically held while being polished or otherwise operated upon.

Also it is an object to provide such a switch having a rocker motion and one which may constitute a unit certain of whose parts function dually as a bearing for the switch shaft and as means of attachment to the polishing or equivalent machine.

It is also aimed to provide the switch for pedal operation, novel spring means to normally hold the switch contact fingers in place engagement with one set of fixed contacts to establish a magnetic circuit, said contact fingers also being rockable to disengage said fixed contacts and at their other extremities engage other fixed contacts, suitable cross conductor connections being provided between the contact fingers and different fixed contacts to dissipate the magnetic action or open the magnetic circuit, and further to provide the switch generally of novel construction capable of operation with minimum arcing incident to operation.

Various additional objects and advantages will be pointed out and otherwise become apparent from a consideration of the description following taken in connection with the accompanying drawings, wherein:

Fig. 1 is a plan of the control switch unit with the cover removed to disclose details;

Fig. 2 is a vertical section through the unit taken on the plane of line 2-2 of Fig. 1

Fig. 3 is an elevation of the pedal for operating the control switch reversed and looking from the upper end of Fig. 1;

Fig. 4 is an elevation of the control spring for the pedal operated shaft of the switch unit;

Fig. 5 is a fragmentary elevation of a bearing ring wherein my contacts switch unit may be employed;

Fig. 6 is a perspective view of a mounting adapter which may be used in connection with the control switch unit;

Fig. 7 is a perspective View showing a modified form of control switch having two phase connections; and

Fig. 8 is a perspective view of the means for giving added magnetic holding power.

The instant invention is particularly useful in apparatus having means for magnetically holding ball-bearing rings or the equivalent while being polished or otherwisev treated and is hereinafter so described although it is to be understood that this is but one example since the invention has broader use and application, and for instance in screw-threading machines, in order to reverse the direction of rotation of the shaft which returns the thread cutter, and also in machines for holding objects for grinding or other operations.

Referring specifically to the drawings wherein like refice erence characters designate like or corresponding parts throughout the different views, the control switch unit is generally designated S and employs a casing of separate parts such as container 10 and cover 11. It usually constitutes an attachment for a polishing apparatus or machine fragmentarily shown at A and may be fastened to a suitable support preferably said polishing apparatus by any suitable means either interiorly or exteriorly thereof in any suitable position. All interior walls of the container and cover are lined with insulation as at I.

Extending rigidly from the container section 10, is an exteriorly screw-threaded tubular nipple 12 which is detachably passed through a part of apparatus A as in Fig. 5, and rigidly secured in place by lock nuts 13 threaded on said nipple. In other instances an adapter 14 as shown in Fig. 6 may be used, such adapter having a plate 15 which may be attached to the apparatus or support by bolts passed through slots 16 therein. Lugs 17 rise from plate 15 and the casing rests thereon (as best shown in Fig. 2) with nipple 12 extending through an opening 18 of a vertical plate 19 of the adapter. Said nipple is rigidly fastened in place (as best shown in Fig. 1) by lock nuts 20 similar to those at 13.

The apparatus or machine A has a conventional magnetic chuck or holder mechanism B whose chuck C is mounted for rotation by electric motor M. Said chuck is magnetized and demagnetized to hold respectively by attraction and release incidental to polishing or the like an object such as a ball bearing ring R. Said holder mechanism B includes a grooved metal disk D rotatable with the chuck arranged to be so wiped by brushes b of a mounting H fastened by a resilient bracket h to the apparatus to give added magnetic holding power to the chuck.

Electric current from any suitable source is supplied through a switch D, which may be a push button switch, the current passing through the conductor means at E to the motor M to energize the same and rotate the chuck C. At the same time the current through the conductor means F passes through the switch 8 and therefrom through the conductor means G to brushes b of the magnetic holder means B in order to magnetize the same and magnetize the chuck C. It is to be understood that with the switch D closed, motor M always rotates in order to rotate the chuck C and according to the operation of the switch S as hereinafter pointed out, the current will alternately magnetize and demagnetize the mechanism B and clutch C in order to hold and release the ring or other article R.

Said control switch S has a shaft 21 which is journalled in opposite walls of the container section 10 and in the nipple 12, preferably being operable through a foot treadle 22 although it may be operated otherwise if desired. The foot pedal has an arm 23 which fits on to the shaft 21 and is rigidly' secured in place by one or more screws 24. Extending from one of the lock nuts 20 is a lug 25 which enters a cut-out portion 26 of the arm 23 and serves to limit the extent of movement of the crank and accordingly of the shaft 21. At the other end of shaft 21 exteriorly of the container is a slot 27. 28 designates a wire spring which is adapted to maintain the switch in one position and permit movement thereof to another position upon depression of the pedal 22. Spring 28 has a coil portion 29 mounted about the free end of shaft 21 with a terminal lug 30 disposed in the slot 27. Such spring is shown in a normal position in Fig. 4, and it has an arm 31 which is movable from the position of Fig. 4 to that of Fig. l to tension it and to be secured to the container section 1t) by a cleat 32.

Disposed on a flat portion of the shaft 21 within the housing is an elongated blade 33 of insulation. Passing through such blade are a number of studs 34 which are screwthreaded at their inner ends into the shaft 21. Said blade 33 in its upper surface has a number of slots 35 extending across the same, and which are occupied by double-ended contact fingers 36. Studs 34 also extend upwardly through the holes in said Contact fingers 36. Expansive coil springs 37 surround the studs 34 above contact fingers 36 and at one end press against the same. Said coil springs 37 are contracted and so held as by washers 38 disposed on the studs 34 and held in place as by cotter pins 39. It is to be noted that the terminal ends of the contact lingers 36 are curved and, further, said contact fingers are somewhat loosely fitted in the slots 35 and on the studs 34 so that they may freely move when engaging and disengaging associated contacts in a wiping movement in order to minimize arcing.

Bolted to the container section 1t) as at 40 are bars of insulation 41, the same being equidistantly spaced from and on opposite sides of a vertical line passing longitudinally through the axis of shaft 21. Disposed along each of the bars 41, and one for each terminal of the ngers 36, are contacts 42. It will be noted that the contacts 42 are of L-shape and one angle thereof is preferably intertted into the adjacent vertical sides of the bars 41.

Reverting to the conductor means F, it will be noted that same includes a conductor 43 for each right-hand contact 42 and that the same is secured thereto by a screw 44 which also serves to fasten the contact to the associated bar 41. In Figs. 1 and 2, a conductor 45 bridges the central contacts 42 being fastened thereto by screws 46. Two wires, unconnected to each other but in crossed relation for current reversing purposes are shown at 47, and the opposite terminals of each of said wires are fastened by screws 48 to diagonally opposed contacts 42, while to the other diagonally disposed contacts 42 the other wire 47 is fastened as by screws 49. Conductor means G includes a conductor 50 for each contact 42 of the associated bar 41, being fastened thereto by screws 51 which also secure the associated contacts 42 to the associated bar 4l. Conductors 52 are fastened by screws 53, one to each double-ended contact 36 and to a binding post means 54 mounted by a bar of insulation 55 fastened in one upper corner of the casing section 10, the binding posts accommodating wires of the conductor means G forming no specic part of the present invention.

In operation, normally with the switch D closed, the

motor M will be energized and will rotate the chuck C` and at the same time current will pass through the conductor means F with the nger contacts 36 in the posil tion shown in full lines in Fig. 2, whereby their engagement with the associated contacts 42 provides a circuit which includes the conductor means G and magnetic mechanism B which magnetizes the chuck C so that the ring R will be held to the chuck C by magnetic traction and the ring at the same time rotates. Any polishing operation, manual or otherwise, during such holding and rotation of the ring may be effected. In order to release the ring R, the magnetic circuit is broken and the ring R is free to drop by gravity. To effect such release and open the magnetic circuit, pedal 22 is depressed, which will rock the shaft 21 and parts carried thereby so as to break contact between the contacts 36 and 42 at the left in Fig. 2 and engage the contacts 36 with the contacts 4Z at the right of Fig. 2, which, it will be realized, reverses the current at the conductors 47. This reversal or demagnetizing of the mechanism B and its chuck C is designed only to be momentary, and as soon as it contacts to release a ring R and replace it by another, and it is to be clear that during such release and interchange of the rings R, the motor M and the chuck C continue to rotate. The mechanism described relates to a threephase system, but it is to be understood that the principles of the invention may be equally well practiced in a twophase system as suggested in Fig. 7. In such an event, in lieu of the insulation bars 41, I use insulation bars 41a mounting them in the circuit as shown in the preceding gures. These bars may be bolted or otherwise fastened to the casing by bolts or the like passed through holes 60 of the bars. Only two L-shaped contacts 42a like those at 42 are employed for each bar 41a, the wires 43a from conductor means F being fastened thereto by screws 44a. The contacts 42a of the other bar 41a have the wires 50a of the conductor means G screwed thereto as at 51a. Crossed wires or conductors unconnected with each other and designated 47@L are bolted at 60a to diagonally opposed contacts 42a.

Various changes may be resorted to provided they fall within the spirit and scope of my invention.

I claim as my invention:

A control switch apparatus having a housing, a hollow element extending laterally exteriorly thereof, adapter means to secure the housing to a support, a wall on said adapter means through which said element passes and to which it is fastened, lug means on the adapter on which the housing rests, switch mechanism within said housing including an operating shaft extending across and through the housing, said shaft being journalled in said element, and operating means carried by said shaft and located exteriorly of the housing, said shaft interiorly of the housing having a flat portion, a blade of insulation disposed against said at portion and extending laterally beyond both sides thereof providing a surface outwardly spaced from the shaft, said surface having slots therein, generally arched contacts loosely straddling said blade and occupying said slots and at both terminals being offset by the blade beyond the shaft and extending below the blade to coact with other contacts, studs extending laterally from the shaft passing through said blade and arched contacts, and tensioned retaining springs mounted on the studs biased against said arched contacts.

References Cited in the file of this patent UNITED STATES PATENTS 1,012,081 Howe Dec. 19, 1911 1,283,226 Leake Oct. 29, 1918 1,677,744 Bishop et al. Iuly 17, 1928 2,148,473 Joy Feb. 28, 1939 2,239,155 Levich Apr. 22, 1941 2,309,039 Bluemle et al. Jan. 19, 1943 2,381,688 Reiff Aug. 7, 1945 FOREIGN PATENTS 587,439 Germany Nov. 4, 1933 

